1. Field of the Invention
This invention relates to judgment of the rightness or authorization of a medium. More specifically, this invention concerns a program, a medium, a method, and a system making use of a computer that judges whether the medium is authorized based on the program.
2. Description of the Related Art
Up to now, digital contents, such as application software, static images, and moving images, are sold or distributed widely as a shape stored in CD-ROM (Compact Disc-Read Only Memory) compatible media. With this view, a writable CD (CD-R:CD-Recordable, CD-RW:CD-ReWritable, and so forth) is utilized widely as a distribution medium of the contents. And a hybrid type CD which has a read-only area and a recordable area in one medium is being developed now as a new distribution medium of the contents. Sellers or distributors of digital contents are starting to market or distribute the hybrid type CD with digital contents stored in a read-only area of the disc, as a substitute for CD-ROM.
Methods have been proposed for preventing the contents stored in those discs from being replicated to another medium illegally. For example, the following art is disclosed in Japanese Laid-open patent application 2000-100068. A computer encodes contents based on each piece of unique information recorded in each disc the contents are stored in, and records the encoded contents on its disc. In case of reproducing the contents, the computer decodes the encoded contents with the unique information in the disc.
The following art is disclosed in Japanese Laid-open patent application 2000-123479. A computer records ID information on an optical disc drive used by an authorized user of a disc. A computer compares the ID information recorded on the disc and ID information on the optical disc drive in use before starting a program stored on the disc. If two pieces of the ID information match, the computer starts the program.
In Japanese Laid-open patent application 1999-167769, a disc and a reproduction permission medium (e.g., IC card) are put in a reproduction apparatus. The apparatus reads reproduction administrative information from the disc and reproduction permission information from the IC card. The apparatus can reproduce contents in the disc corresponding to a result of collating two pieces of the information.
A disadvantage associated with the above-described methods is that they require a unique optical disc apparatus corresponding to methods for preventing illegal or unauthorized replications in case of processing (producing etc.) information about contents or the like.
An object of the present invention is to eliminate the use of a unique optical disc apparatus from processing information stored in a disc. It is also an object of the invention to put limitations on use of a disc replicated illegally or wrongly with a general optical disc apparatus, or to make it impossible to use such an illegal, wrongful or unauthorized disc.